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The Om Programming Language

om-language.com

297 pointstosh111 comments

Would recommend placing example language syntax above the fold. Was tough to have to scroll halfway down the entire site to see any syntax. Nobody cares about the EBNF syntax until they have a feel for the language.

Alt opinion: syntax is the least important part of a programming language. I can't wait for the day someone invents one where it's defined entirely as an AST (with the S standing for Semantic). Just bring your own weird syntax.

I guess Unison is the closest to this platonic ideal right now? https://github.com/unisonweb/unison/issues/499

I completely agree: If it is ugly-as-sin-but-useful I will learn it.

The aesthetic of mathematics as it appears in journals is I think questionable, but undeniably convenient for communication, so it is every language making the case that you (dear reader) can say something very complicated and useful in the ideal amount of space.

"Hello world" isn't that: That's the one program everyone should be able to write correctly, 100% of the time. That's how we can talk about brainfuck as exercise, but APL is serious.

Or put another way, even if seeing a new kind of "hello world" excites dear reader, it's probably not going to excite me, unless it's objectively disgusting.

What Om does here is exactly right for me: It tells me what it is, and makes it easy for me to drill down to each of those things to figure out what the author means by that, and decide if I am convinced.

I mean, that's the point right? I'm here trying to learn something new and that requires I allow myself to be convinced, and since "hello world" is table-stakes, seeing it can only slow my ability to be convinced.

I have an idea, maybe we could represent that AST as parenthesis.

Honestly, we can do better than LISPs.

Just use curly brackets and boom. LISP 3k.

You're welcome.

It can even be used to represent serialized objects...

That's cool, but I might prefer semantic whitespace. Sure would be neat if we could both work with the same code in our preferred forms.

Like this? https://en.wikipedia.org/wiki/Whitespace_(programming_langua...

Ah yes, now there is a LISP I can get behind!

Love this take! Unison is exactly this, and it's awesome!

Here's a quote from one of the creators:

> But here's the super cool thing about our language! Since we don't store your code in a text/source code representation, and instead as a typechecked AST, we have the freedom to change the surface syntax of the language very easily, which is something we've done several times in the past. We have this unique possibility that other languages don't have, in that we could have more than one "surface syntax" for the language. We could have our current syntax, but also a javascript-like syntax, or a python-like syntax.

https://news.ycombinator.com/item?id=46053304

Can Raku do something like this? I was lightly exploring it recently, and I thought I saw that something like this may be possible with it.

I'm not super familiar with Raku, but if RakuAST is what you had in mind it looks a bit different:

    use experimental :rakuast;
    
    my $ast = RakuAST::Call::Name.new(
      name => RakuAST::Name.from-identifier("say"),
      args => RakuAST::ArgList.new(
        RakuAST::StrLiteral.new("Hello world")
      )
    );

Looks more like "low-level programming an AST" (which I believe other languages offer as well), rather than using a bidirectional transform. I don't know how you'd get Raku code back out, for example.

Edit: I should have looked deeper, `DEPARSE` does exactly this:

https://docs.raku.org/type/RakuAST

Neat!

It also goes from source code to AST:

  $ raku -e 'say Q|say "Hello World!"|.AST'
  RakuAST::StatementList.new(
    RakuAST::Statement::Expression.new(
      expression => RakuAST::Call::Name::WithoutParentheses.new(
        name => RakuAST::Name.from-identifier("say"),
        args => RakuAST::ArgList.new(
          RakuAST::QuotedString.new(
            segments   => (
              RakuAST::StrLiteral.new("Hello World!"),
            )
          )
        )
      )
    )
  )

thanks, all.

This is a Very Bad Idea. Two people working with the same language will be unable to reason about each other's code, because it requires understanding their bespoke syntax and its nuances.

No it won't? That's exactly the point -- each of those people will be viewing the code in their own preferred syntax. If there is semantic nuance in the writer's syntax, the reader will see it presented in the best way their preferred syntax's representation can provide.

Imagine all the hours saved that are currently spent on tired tabs vs spaces debates, or manicuring .prettierrc, etc etc. The color of the bike shed might matter (sometimes a lot) to some people, I know, but it's storing bikes away from the elements and thieves that is the goal, not obsessing over optimizing something that is demonstrably a subjective matter of taste.

Those are both formatting examples though? You're suggesting totally different syntaxes, which means you can't even point to the same line in a codebase when talking about a PR. This throws up massive hurdles around communication when you could just agree on one standard and move on.

  class Bean {
    private boolean sprouted;

    public void sprout() {
      this.sprouted = true;
      // ...
    }
  }

  data Bean = Dormant | Sprouted
  
  sprout :: Bean -> Bean
  sprout Dormant = Sprouted
  sprout Sprouted = -- aw, beans, we could have modeled
                    -- this state as impossible to construct,
                    -- but you chose runtime checks, so
                    -- here we are.

As for pointing to the source line, I think JavaScript people solved that one for us with source maps. Just because we download and execute a single 4Mb line of minified code, doesn't mean we can't tell which line of the original source caused the error. :)

Oh lord, yeah this convinces me even more that this is a bad idea. I can't even tell at a glance if those do the same thing. Just pick one and move on, you're requiring everyone to pass around sourcemaps literally everywhere they go, one for every single pair of syntaxes. You can't even talk about the code with the same language with each other. Is Bean a "class" or a "datatype"? If I'm using one syntax, how do I tell you to fix a bug in your syntax?

> If I'm using one syntax, how do I tell you to fix a bug in your syntax?

How about "Hey, your Bean ain't sprouting"? :)

I'm sorry, I feel like I'm not communicating this properly. Um, have you ever discussed with someone a book or a TV show that was translated into your language? Did you have problems referring to the exact parts you liked or disliked? :)

Last commit is from 2 years

Ah, thought it was new.

Almost every site for a new language that gets posted here does this. Every time someone points out how they don't care about anything until they've seen what code actually looks like. I'm surprised this still happens.

Aren't LLMs supposed to write machine code directly, no more programming languages at all, any day now? Joking aside, programming languages are a good mental exercise. Forth was my first language after assembly. Didn't like the stack juggling and ended up using its macro assembler more and more, it became something else, conventions over code I suppose, like what to keep in registers. Forth (and Unix) got the composability requirement right, the testing of individual units.

I'm still waiting to see the first show HN I made a language designed for LLMs to write programs better.

It came up a few weeks ago already, can't find the link

There have been a few.

A few days ago I asked Claude what kind of language it would like to program in, and it said something like Forth but with static typing, contracts, and constraint solving, implemented on the Erlang BEAM.

So I have been prodding Claude Code for a few sessions to actually do it. It's a silly experiment, but fun to watch. Right now it's implementing a JSON parser in the generated language as a kind of milestone example.

If you don't mind, could you drop some code? I'd be interested to see the result :)

sure, for example it generated this small demo of the type and contract safeguards. As you can see, it's mostly "Forth but with things":

  # bank.ax — The Safe Bank (Milestone 2)
  #
  # Demonstrates property-based verification of financial operations.
  # Each function has PRE/POST contracts. VERIFY auto-generates random
  # inputs, filters by PRE, runs the function, and checks POST holds.
  
  # DEPOSIT: add amount to balance
  # Stack: [amount, balance] (amount on top)
  # PRE: amount > 0 AND balance >= 0
  # POST: result >= 0
  DEF deposit : int int -> int
    PRE { OVER 0 GTE SWAP 0 GT AND }
    ADD
    POST DUP 0 GTE
  END
  
  # WITHDRAW: subtract amount from balance
  # Stack: [amount, balance] (amount on top)
  # PRE: amount > 0 AND balance >= amount
  # POST: result >= 0
  DEF withdraw : int int -> int
    PRE { OVER OVER GTE SWAP 0 GT AND }
    SUB
    POST DUP 0 GTE
  END
  
  # Verify both functions — 500 random tests each
  VERIFY deposit 500
  VERIFY withdraw 500
  
  # Prove both functions — mathematically, for ALL inputs
  PROVE deposit
  PROVE withdraw
  
  # Demo: manual operations
  1000 200 deposit SAY
  1000 300 withdraw SAY

Running it outputs:

  VERIFY deposit: OK — 500 tests passed (1056 skipped by PRE)
  VERIFY withdraw: OK — 500 tests passed (1606 skipped by PRE)
  PROVE deposit: PROVEN — POST holds for all inputs satisfying PRE
  PROVE withdraw: PROVEN — POST holds for all inputs satisfying PRE
  1200
  700

How does it do the proving?

Spawns and calls z3 under the hood, I did let it cheat there because otherwise it's rabbit holes below rabbit holes all the way down :)

thanks.

So instead of using programming languages designed specifically to effectively express algorithms and data structures, we are going to use natural language like English that is clearly not expressive enough for this? It’s like rewriting a paper about sheaf cohomology in plain English without any mathematical notation and expecting it to be accessible to everyone.

:) Not exactly. We'll use English to get a kinda description, then test and debug to make that functional, then cycling the functionality with users to nail down what is actually needed. Which won't be written down anywhere. Like before. Except with autocomplete that tries to predict a page or two of code at a time. Often pretty accurately.

I do not think you are saying same thing here :). No one doubts we can put "make a todo app" into english, and that you can yeah test with users. But that's different from a task which would articulate, in only english, the precise layout and architecture of the MVC that make the app possible.

English is fine, but I am personally a lot faster in my mind and fingers and IDE with a language suited for this stuff. AI guys just want to be teachers deep down I think :).

Conrad Barski, Feb 25, 2026:

> Working atari 2600 flappy bird, by just asking chatgpt to directly output the raw bytes for a cartridge image

TBH this is a bit unexpected: it should know how to encode instructions, of course, but calculating all jumps on the fly is rather hard (I think).

Let's have more programming language posts (even about "retro" ones like Icon, SNOBOL, Bliss, MUMPS, etc.), guys.

And less about AI topics.

Om.

https://emojipedia.org/om

https://en.wikipedia.org/wiki/Om

if everyone on HN started downvoting all the AI posts (atleast the slop ones) it would cut down submissions by half

I think it's going to take some time for the reality of ns;nt and the disappointments to sink in. They need to learn that one cannot "claw" their way to a money machine.

And therein lies the tragedy of folks exploiting well known culturally loaded symbols/concepts for attention/etc. on the Internet.

For example, I really don't know what to make of this similarly named language; enthusiastic kid or attention-seeking influencer? - https://omlang.com/

people exploit anything for attention/etc. on the Internet.

A more explanatory article mentioned in the post: https://evincarofautumn.blogspot.com/2012/02/why-concatenati...

ah, thanks, that's why my first thought was that "hey, this feels very FORTH like"

I worked with Jason (creator of Om) at my last job. He's awesome!

is it his first language design ?

> any UTF-8 text (without byte-order marker) defines a valid Om program.

What is the behavior of a program with unmatched braces? I am not sure a stray `}` would fit any of the defined syntax.

https://www.om-language.com/index.html#language__syntax__

That would be parsed as a single operator and evaluated using the following rule:

> Evaluates to the operation defined for the operator in the environment. If none, evaluates to a constant function that pushes the operator, followed by all input terms, onto the output program.

I believe it would simply output itself.

I like how it unifies the operation stream with the stack (by pushing outputs back into the operation stream to process next).

An even simpler model than Forth, which evaluates an operation stream, with words that operate on a stack. And as noted, this makes recursion trivial.

Another concatenative-ish one embedded in js .. just for fun - https://github.com/srikumarks/pjs

You may find the "genailang" module fun to play with.

Om = Forth + Tcl ?

We've already seen Forth + Lisp

What's next? Lisp + Tcl ? Or maybe: Lisp + Forth + Tcl ? ;)

Forth + APL: Uiua

There are also APL + Lisp variants, like April, or even q from kdb+/q (kinda like Lisp but without parens).

---

The APL programming language (a subset thereof) compiling to Common Lisp.

https://github.com/phantomics/april

APL and LISP—should they be combined, and if so how?

https://dl.acm.org/doi/10.1145/800136.804474

I get the feeling there is something interesting here, but the website seems myopically focused on syntax. It doesn't really tell me what this language is good at or how you'd expect people to use it.

I confused this with https://github.com/omcljs/om

Yeah Om was an extremely widely used Clojurescript library many years ago (maybe still is), and to me that's what this word will always refer to.

I think Hinduism might have a prior claim.

https://news.ycombinator.com/item?id=47161422

Has the CSS failed to load for me, or are the syntax diagrams meant to be that wide and blurry?

They are, works better on mobile but I don't like these diagrams, I think EBNF is more readable.

What is the meaning and reason behind the choice of this specific name for the language?

The only two letter combination that is not already used by another language.

This language is going to be a SuperHitPopular in India !!!

Missing a 'g'!

Omg would have a ring to it.

May I introduce you to the ultimate level of conciousness: https://en.wikipedia.org/wiki/Om

When you realize you were the missing "g" all along.

Outstanding work

Will never not complain about languages not giving code examples. It’s like writing a charting/UI/style library and showing no examples. Just what?

You overlooked the examples. They might not satisfy you, but there are examples.

To be fair, the examples are extremely easy to overlook. They are also, to put it delicately, not the most helpful.

apparently fold example is very helpful to some.

Absolutely agree. But fairness precludes denying the existence of examples.

They are not prominent, but they are in a section with the heading 'Examples'.

The examples are fine for an early-stage poc project like this one. `minutes` with evaluation trace and `[Fold]<-` are illustrative, and if you work them out with pen and paper, you can get a good grasp on the main ideas of the language. That you have to search for them on a page that looks like a slightly-formatted README instead of having a nice scrollable with syntax-highlighted snippets at the top is because this IS a slightly-formatted README - and that's also completely fine at this stage. What's important is that there are a few interesting concepts there and that it was published. Even if this one fizzles, as 99.999% of languages do, that doesn't matter if some other language down the line gets inspired by those concepts.

if it's something you do 100% of the time, is it really adding any information to the world?

absolutely does! for a new language that no one has heard of, it is essential that examples make at least a parallel with other languages. providing examples for mundane things is very useful to build the understanding with the reader who hasn't been writing a paper on OM language.

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